21045313 has 8 divisors (see below), whose sum is σ = 21281832. Its totient is φ = 20810496.

The previous prime is 21045301. The next prime is 21045317. The reversal of 21045313 is 31354012.

It can be written as a sum of positive squares in 4 ways, for example, as 2096704 + 18948609 = 1448^2 + 4353^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21045313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21045317) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62281 + ... + 62617.

It is an arithmetic number, because the mean of its divisors is an integer number (2660229).

Almost surely, 2^21045313 is an apocalyptic number.

It is an amenable number.

21045313 is a deficient number, since it is larger than the sum of its proper divisors (236519).

21045313 is a wasteful number, since it uses less digits than its factorization.

21045313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 851.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 21045313 is about 4587.5170844369. The cubic root of 21045313 is about 276.0907117988.

Adding to 21045313 its reverse (31354012), we get a palindrome (52399325).

The spelling of 21045313 in words is "twenty-one million, forty-five thousand, three hundred thirteen".